This is straight from Google. Finally, Nexus One owner do not need to download the floating leaked updates. In the coming week, all the Nexus One owner will receive the official OTA Android 2.2 update.
Nexus One Blog today reported that In order to access the update, you will receive a message on your phone’s notification bar. Just download the update, wait for it to install, and you should be all set. This update will be rolled out gradually to phones – and most users will receive the notification by the end of the week . We hope you enjoy these new features.
So just wait and watch.